. Bulletin. Natural history; Natural history. 356 Illinois Natural History Survey Bulletin Vol. 30, Art. 5. Fig. 15.—The Alton navigation pool of the Illinois River at Hardin. Photo by the author. ductive enough in 1966 to support a commercial mussel fishery. At least 38 different kinds of mussels were taken from this pool in 1912 by Danglade (1914:37), whereas only 20 kinds were collected there in the 1966 survey (Table A-3). However, fewer species have been eliminated from the Alton pool than have been extirpated elsewhere in the river during the past 54 years (Fig. 10). Also, in 1966 mussel
. Bulletin. Natural history; Natural history. 356 Illinois Natural History Survey Bulletin Vol. 30, Art. 5. Fig. 15.—The Alton navigation pool of the Illinois River at Hardin. Photo by the author. ductive enough in 1966 to support a commercial mussel fishery. At least 38 different kinds of mussels were taken from this pool in 1912 by Danglade (1914:37), whereas only 20 kinds were collected there in the 1966 survey (Table A-3). However, fewer species have been eliminated from the Alton pool than have been extirpated elsewhere in the river during the past 54 years (Fig. 10). Also, in 1966 mussels were much more abundant there than they were in the other pools except for one small area just below Peoria Lake and in Lower Peoria Lake (Fig. 11). Only in the Alton pool were conditions suitable in 1966 for the support of relatively large- sized populations of pimple-backs {Q. pustulosa) and washboards (M. gigan- tea) and moderate-sized populations of warty-backs (Q. nodulata) and three- horned warty-backs [O. reflexa). The species composition and abundance of mussels in the Alton pool in 1966 clearly indicated that by the time the water reached this pool some semblance of re- covery in water quality had occurred although not enough to support the va- riety and numbers of mussels known to have existed there in 1912. Richardson (1921a: 405) noted that in the Alton pool: "Inside the 7-foot line in 1915 a soft light-colored silt 2 inches to more than 12 inches deep was found at most of our collecting ; Siltation probably has limited the dis- tribution and abundance of such spe- cies as the yellow sand-shell (L. a. f. anodontoides) during the past 75 or more years in this pool. However, the prime limiting factor in the Alton pool prob- ably has been the effects of domestic and industrial pollution from upstream sources. A comparison of the collections of mussels made in the vicinity of Mere- dosia (river mile ) between 1912 and 1966 indicated that the m
Size: 2319px × 1078px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., booka, bookcentury1900, bookdecade1910, booksubjectnaturalhistory
